X0306 4 2020-06-15 0 0001510487 Principia Biopharma Inc. PRNB 0001751790 Wolff Stefani C/O PRINCIPIA BIOPHARMA INC. 220 E. GRAND AVENUE SOUTH SAN FRANCISCO CA 94080 0 1 0 0 Chief Development Officer Common Stock 2020-06-15 4 S 0 400 59.8925 D 24200 D Common Stock 2020-06-15 4 S 0 5004 60.8095 D 19196 D Common Stock 2020-06-15 4 S 0 100 61.368 D 19096 D The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan. Represents the weighted average sales price per share. The shares sold at prices ranging from $59.18 to $60.13 per share. Upon request by the Commission staff, Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price within the range set forth in this Form 4. Represents the weighted average sales price per share. The shares sold at prices ranging from $60.20 to $61.17 per share. Upon request by the Commission staff, Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price within the range set forth in this Form 4. /s/ Christopher Y. Chai, Attorney-in-Fact for Stefani Wolff 2020-06-17